This invention relates to seals for temporarily sealing a toner bin or the like, and particularly, to a toner bin seal for use in sealing the toner container or hopper of a xerographic printer or copier cartridge. The invention also encompasses a method for providing a secure temporary seal for a toner bin container or the like.
Many xerographic devices including laser printers and small copiers utilize cartridges that contain a supply of xerographic toner material. These cartridges must be replaced from time to time as the toner is used up in the xerographic process. The cartridges commonly include the xerographic magnetic roller assembly and a toner bin assembly with a container or hopper for containing the required supply of toner material. The roller assembly is positioned above an opening in the toner container in position to pick up toner material from the container as required by the particular xerographic device in which the cartridge is used. Although, the toner in the toner bin container must be exposed to the magnetic roller in order for the xerographic device to operate properly, the toner comprises a fine powder material and must be sealed in the toner container or hopper for shipping and handling.
The toner container seals provided by cartridge manufacturers are commonly placed in a narrow slot formed between the container and a structure connected over the container opening that holds the magnetic roller assembly. The seal is formed in the cartridge manufacturing process before any toner is placed into the toner container. A slot opening is provided along one edge of the container by which the original seal may be easily removed prior to installing the cartridge in the particular xerographic device.
Although printer and copier cartridges were commonly designed to be discarded after the original toner supply was exhausted, the magnetic roller and other mechanisms in the cartridges have useful lives substantially longer than the toner life. Thus, the cartridges could be recharged or refilled with a supply of toner and reused several times. However, the restricted access to the slot formed over the container opening made it difficult to provide an effective seal when a used cartridge was recharged with toner. Imperfect seals over the refilled toner containers resulted in substantial loss of toner during shipment and handling and gave the recharged cartridges a shorter life span.
Prior to the present invention, various types of separator cards were employed to reduce the loss of toner during shipment. The separator cards were inserted into the toner bin slot through the slot opening so as to substantially cover the container opening. Although, the separator cards did cover or block the majority of the toner container opening, they did not provide an actual seal around the toner container or hopper opening. Some separator cards were formed from a plastic material and were adapted to rest more or less loosely in the slot. Other separator cards were provided with magnetic properties that drew the separator card material against the container opening for reducing leakage. However, even the magnetic separator cards did not provide a complete seal and did allow substantial amounts of toner to escape from the toner container during shipment and handling. In addition to the plain plastic and magnetic separator cards, one separator card sold under the trademark FIRMLOCK included an arrangement for biasing the separator card material against the material around the opening of the toner container. However, these biased separator cards were difficult to insert and also failed to provide a complete seal.